Ignition distributor for internal combustion engines

Abstract

The distributor comprises a rotatably mounted rotor, which has close to its axis of rotation a first electrode and has at its end that is remote from the axis of rotation a second electrode, which is connected by an electric line to the first electrode. The distributor also comprises a housing, which is closed by a cap, which is provided on its inside peripheral surface with a plurality of peripherally spaced apart fixed electrodes for cooperating with the second electrode of the roto. The cap is further provided on its inside surface with a center electrode, which terminates at a distance from the first electrode of the rotor to form a spark gap therewith. To form a positive joint with the cap the embedded portion of the center electrode has a non-cylindrical peripheral surface, which is rounded and free of any edge.

We claim: 
     
       1. In an ignition distributor for internal combustion engines, comprising housing means,   a rotor mounted in said housing means for rotation about an axis and having an outer end remote from said axis, which rotor is provided near said axis with a first electrode and at said outer end with a second electrode, which is electrically conductively connected to said first electrode, and   a cap, which closes said housing means and has an inside surface facing said rotor and is provided on said inside surface with a plurality of peripherally spaced apart fixed electrodes, which are embedded in said cap and adapted to cooperate with said second electrode, said cap being also provided on said inside surface with a center electrode, which terminates at a distance from said first electrode to define a spark gap therewith and comprises an embedded portion, which is positively embedded in said cap and to effect this it has a non-cylindrical peripheral surface,   the improvement residing in that said non-cylindrical peripheral surface in said embedded portion is rounded and is free of edges.   
     
     
       2. The improvement set forth in claim 1, wherein said non-cylindrical peripheral surface in said embedded portion is free of surface portions having a radius of curvature which is not in excess of 0.5 mm. 
     
     
       3. The improvement set forth in claim 1, wherein said non-cylindrical peripheral surface in said embedded portion is free of surface portions having a radius of curvature which is not in excess of 1 mm. 
     
     
       4. The improvement set forth in claim 1, wherein said non-cylindrical peripheral surface of said embedded portion has in longitudinal section a non-rectangular configuration and has in cross-section a non-circular configuration. 
     
     
       5. The improvement set forth in claim 1, wherein said embedded portion has an oval shape in cross-section at least in part of its length. 
     
     
       6. The improvement set forth in claim 1, wherein said fixed electrodes are provided with edges in a portion, with which they are embedded in said cap. 
     
     
       7. The use of a center electrode which is positively embedded with a non-cylindrical portion of its peripheral surface in the cap of an ignition distributor for internal combustion engines and which is rounded avoiding any edges in said portion in order to prevent the formation of cracks or fissures in said cap due to a combined thermal and electrical impact on said cap of such an ignition distributor which is to be mounted directly on the engine block and in which the center electrode terminates at a distance from its opposite electrode at the ignition distributor rotor thereby forming a spark gap between said center electrode and said opposite electrode.